Serological based monitoring of a cohort of patients with chronic Chagas disease treated with benznidazole in a highly endemic area of northern Argentina.

This study aimed to evaluate well-documented diagnostic antigens, named B13, 1F8 and JL7 recombinant proteins, as potential markers of seroconversion in treated chagasic patients. Prospective study, involving 203 patients treated with benznidazole, was conducted from endemic areas of northern Argentina. Follow-up was possible in 107 out of them and blood samples were taken for serology and PCR assays before and 2, 3, 6, 12, 24 and 36 months after treatment initiation.

Serodiagnosis of chronic and acute Chagas' disease with Trypanosoma cruzi recombinant proteins: results of a collaborative study in six Latin American countries.

An enzyme-linked immunosorbent assay to diagnose Chagas' disease by a serological test was performed with Trypanosoma cruzi recombinant antigens (JL8, MAP, and TcPo). High sensitivity (99.4%) and specificity (99.

DNA immunization with the ribosomal P2beta gene of Trypanosoma cruzi fails to induce pathogenic antibodies.

Patients with chronic Chagas' heart disease (cChHD) develop a strong IgG response against the C-terminal region of the Trypanosoma cruzi ribosomal P2beta protein (TcP2beta). These antibodies have been shown to exert an in vitro chronotropic effect on cardiocytes through stimulation of the beta1-adrenergic receptor (beta1-AR). Moreover, the presence of antibodies recognizing the TcP2beta C-terminus was associated with cardiac alterations in mice immunized with the corresponding recombinant protein.

Antigenic properties of the merozoite surface protein 1 gene of Plasmodium vivax.

Plasmodium vivax is responsible for an approximate 35 million yearly human cases of malaria. Unfortunately, due to the low mortality rate associated with it and the difficulties of continuously in vitro culturing of this parasite, vaccine development against this human malaria has been largely neglected. In here, the antigenic properties of the merozoite surface protein 1 gene of P.

Main features of DNA-based immunization vectors.

DNA-based immunization has initiated a new era of vaccine research. One of the main goals of gene vaccine development is the control of the levels of expression in vivo for efficient immunization. Modifying the vector to modulate expression or immunogenicity is of critical importance for the improvement of DNA vaccines.

Antibodies to ribosomal P proteins of Trypanosoma cruzi in Chagas disease possess functional autoreactivity with heart tissue and differ from anti-P autoantibodies in lupus.

Anti-P antibodies present in sera from patients with chronic Chagas heart disease (cChHD) recognize peptide R13, EEEDDDMGFGLFD, which encompasses the C-terminal region of the Trypanosoma cruzi ribosomal P1 and P2 proteins. This peptide shares homology with the C-terminal region (peptide H13 EESDDDMGFGLFD) of the human ribosomal P proteins, which is in turn the target of anti-P autoantibodies in systemic lupus erythematosus (SLE), and with the acidic epitope, AESDE, of the second extracellular loop of the beta1-adrenergic receptor. Anti-P antibodies from chagasic patients showed a marked preference for recombinant parasite ribosomal P proteins and peptides, whereas anti-P autoantibodies from SLE reacted with human and parasite ribosomal P proteins and peptides to the same extent.

Immunization with recombinant Trypanosoma cruzi ribosomal P2beta protein induces changes in the electrocardiogram of immunized mice.

Molecular expression cloning techniques revealed that patients with severe chronic Chagas heart disease showed a strong humoral response against the cloned C-terminal portion of the Trypanosoma cruzi ribosomal P2beta protein, previously named JL5. The main linear epitope of this polypeptide was mapped to the 13 C-terminal amino acid sequence EEEDDDMGFGLFD (named R13), which is almost identical to the mammalian ribosomal P consensus sequence EESDDDMGFGLFD (named H13). Enzyme-linked immunosorbent assay measurements demonstrated that sera from patients with chronic Chagas heart disease presented a very specific anti-P humoral response with high anti-R13, but low H13 antibody levels.

Acquired immune responses to the N- and C-terminal regions of Plasmodium vivax merozoite surface protein 1 in individuals exposed to malaria.

In this study, we evaluated the naturally acquired immune response to Plasmodium vivax merozoite surface protein 1 (PvMSP1) in individuals with recent clinical episodes of malaria from the state of Para, Brazil. Ten recombinant proteins representing the first 682 amino acids (aa) of the N-terminal region and one representing the final 111 aa of the C-terminal region were expressed in Escherichia coli as glutathione S-transferase fusion proteins. Both of these regions have been suggested as candidates for development of a vaccine against Plasmodium sp.

Plasmodium vivax: epitope mapping of monoclonal antibodies against the N-terminal region of the merozoite surface protein 1.

Plasmodium vivax is the most widely distributed human malaria with an estimate of 35 million cases per year. The deduced amino acid sequence comparisons of the Merozoite Surface Protein 1 (MSP1) from several plasmodial species, including that of P. vivax (PvMSP1), revealed the existence of highly conserved blocks and polymorphic blocks.

Plasmodium vivax: dimorphic DNA sequences from the MSP-1 gene code for regions that are immunogenic in natural infections.

The merozoite surface protein 1 gene of Plasmodium vivax (PvMSP-1) is becoming a solid genetic marker for studying the polymorphism of natural parasite populations from this prevalent human malaria. Indeed, a conserved and a variant PvMSP-1 gene segments have been amplified from total genomic parasite DNA obtained from isolates representing seven countries and three continents. Interestingly, the variant PvMSP-1 gene segment contains two highly conserved parental allele forms capable of limited genetic exchange at the sexual stage in the mosquito vector.

Characterization of naturally acquired human IgG responses against the N-terminal region of the merozoite surface protein 1 of Plasmodium vivax.

The primary structure of the merozoite surface protein 1 of Plasmodium vivax (PvMSP-1) revealed the existence of conserved and polymorphic blocks of the protein among different Plasmodium species. To characterize the naturally acquired IgG antibody responses to the PvMSP-1 molecule, the entire N-terminal portion of this protein was expressed as 10 overlapping glutathione S-transferase fusion proteins. The affinity-purified recombinant products were tested by enzyme-linked immunosorbent assay and Western blot against the sera of malaria patients from the state of Rondonia, Brazil.

Longitudinal study of naturally acquired humoral immune responses against the merozoite surface protein 1 of Plasmodium vivax in patients from Rondonia, Brazil.

A longitudinal study on the naturally acquired humoral immune responses against the merozoite surface protein 1 of Plasmodium vivax (PvMSP-1) was performed in malaria patients from the Brazilian Amazon region of Rondonia. We have previously cloned and expressed a recombinant protein, ICB2-5, that encodes 508 amino acids from the N-terminal portion of the PvMSP-1 protein. This affinity-purified polypeptide was tested by an enzyme-linked immunosorbent assay in a one-year longitudinal study using sera from 34 patients who had at least one malaria infection during the study period.

The chronic presence of the parasite, and anti-P autoimmunity in Chagas disease: the Trypanosoma cruzi ribosomal P proteins, and their recognition by the host immune system.

Molecular expression cloning techniques revealed that patients with the severest clinical form of Chagas disease, chronic Chagas heart disease, presented a strong humoral response against the cloned C-terminal portion of a Trypanosoma cruzi ribosomal P protein. Parasite P antigens identification led to characterize the ribosomal P protein system in T. cruzi.

Characterization of the C-terminal region of a Trypanosoma cruzi 38-kDa ribosomal P0 protein that does not react with lupus anti-P autoantibodies.

A Trypanosoma cruzi cDNA lambda gt11 recombinant, C-P0, encoding the carboxyterminus of a highly antigenic ribosomal P protein, was isolated. Sequence comparisons and immunological evidence allowed its identification as the C-terminal region of the T. cruzi 38-kDa ribosomal P0 protein.

Human IgG responses against the N-terminal region of the Merozoite Surface Protein 1 of Plasmodium vivax.

The complete primary structure of the gene encoding the Merozoite Surface Protein 1 of Plasmodium vivax (PvMSP-1) revealed the existence of interspecies conserved regions among the analogous proteins of other Plasmodia species. Here, three DNA recombinant clones expressing 50, 200 and 500 amino acids from the N-terminal region of the PvMSP-1 protein were used on ELISA and protein immunoblotting assays to look at the IgG antibody responses of malaria patients from the Brazilian amazon region of Rondônia. The results showed the existence of P.

Humoral autoimmune response to ribosomal P proteins in chronic Chagas heart disease.

The C terminal region of a Trypanosoma cruzi ribosomal P protein, encoded by the lambda gt11 JL5 recombinant, defined a major antigenic determinant in chronic Chagas heart disease. Immunopurified anti-JL5 antibodies were tested for anti-human ribosome reactivity by immunoblotting. They recognized the parasite ribosomal P proteins and clearly reacted with the corresponding human P proteins.

Major Trypanosoma cruzi antigenic determinant in Chagas' heart disease shares homology with the systemic lupus erythematosus ribosomal P protein epitope.

A Trypanosoma cruzi lambda gt11 cDNA clone, JL5, expressed a recombinant protein which was found to react predominantly with chronic Chagas' heart disease sera. The cloned 35-residue-long peptide was identified as the carboxyl-terminal portion of a T. cruzi ribosomal P protein.

The cloned C-terminal region of a Trypanosoma cruzi P ribosomal protein harbors two antigenic determinants.

A DNA strategy was designed to characterize the antigenic site(s) within a lambda gt11 cloned 35-amino-acid antigenic peptide, identified with antibodies from patients with chronic Chagas' heart disease (cChHD) and systemic lupus erythematosus (SLE) as the C-terminal portion of a Trypanosoma cruzi P ribosomal protein. The 198-bp cDNA insert was digested with AluI, resulting in two DNA segments that were recloned in lambda gt11. To identify specific antigenic determinants, the recombinant phage and the purified recombinant antigens were probed with sera from clinically characterized subjects.

Identification of major Trypanosoma cruzi antigenic determinants in chronic Chagas' heart disease.

To identify Trypanosoma cruzi target antigens in overt Chagas' heart disease, a parasite lambda gt11 cDNA library was screened with the serum of a patient with a severe chagasic heart involvement (JL). Using a phage dot array immunoassay, 5 highly antigenic clones, JL1, JL5, JL7, JL8, and JL9, were probed with sera from clinically characterized T. cruzi infected subjects.